Cross-Fab Wafer Carrier Transfer Without Interface Devices
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Solution Overview
Problem
Existing manufacturing execution systems (MES) and material control systems (MCS) are limited to a single fab and cannot efficiently handle cross-fab and/or cross-AMHS transportation requests, leading to inefficiencies and traffic jams due to the need for interface devices and increased clean room space.
Innovation Solution
A unified control unit communicates with multiple fabs to synchronize manufacturing execution systems, material control systems, and automated material handling systems, enabling direct transfer of wafer carriers between different fabs and AMHSs without the use of intermediate interface devices, optimizing routes based on traffic and priority.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If interface devices are used for cross-fab transportation, then wafer carriers can be transferred between different fabs, but traffic jams occur and clean room space is increased
Solution Approach 1:
The patent introduces a stager as an intermediary device in the bridging area that temporarily stores wafer carriers during cross-fab transfers. This mediator enables coordination between different AMHS systems from different vendors, allowing wafer carriers to be transferred between fabs without direct vehicle-to-vehicle transfer, thus resolving the incompatibility issue while maintaining transportation efficiency
Solution Approach 2:
The patent divides the cross-fab transportation process into separate phases: intra-fab transfer to the stager, inter-fab transfer via the bridging area, and intra-fab transfer from the stager to the destination. This segmentation allows each phase to be optimized independently and prevents traffic jams by distributing transfer operations across different time windows
2Adaptability or versatility
If interface devices are used for cross-fab transportation, then wafer carriers can be transferred between different fabs, but clean room space is increased
Solution Approach 1:
The patent utilizes the bridging area as a separate spatial dimension that connects fabs without requiring extensive clean room space within the fabs themselves. The stager is positioned in this bridging area, allowing cross-fab transfers to occur in a transition zone that does not count toward the clean room footprint of individual fabs
3Device complexity
If MES and MCS systems are limited to single fab, then system complexity is reduced, but cross-fab and cross-AMHS transportation requests cannot be processed
Solution Approach 1:
The patent implements a universal control architecture where the MES and MCS systems can handle both single-fab and cross-fab transportation requests through a unified interface. The system automatically routes requests appropriately - using direct transfer within a single fab or coordinating with staggers for cross-fab transfers - thus providing multi-functionality without proportionally increasing complexity
Data Source
AI summary
System and method for cross-fab wafer transportation are provided. An exemplary system includes a first control unit coupled to an associated first automatic material handling system (AMHS), the first AMHS includes a first overhead transport (OHT) track comprising a first portion and a first vehicle movable along the first OHT track and carrying a container, the container is operable to carry semiconductor wafers therein. The system includes a second control unit coupled to an associated second AMHS, the second AMHS includes a second OHT track comprising a second portion adjacent to the first portion and a second vehicle movable along the second OHT track. When the first vehicle is within the first portion of the first OHT track and the second vehicle is within the second portion of the second OHT track, the first and second vehicles are operable to transfer the container directly from the first vehicle to the second vehicle.